Sensor Mounting in an Implantable Blood Pump

ABSTRACT

Techniques for mounting a sensor are disclosed. In some implementations, a molded interconnect device carries a sensor for transducing a position of a rotor of the implantable blood pump. The molded interconnect device includes one or more integrated electronic circuit traces configured to electrically connect the Hall sensor with a printed circuit board of the implantable blood pump, and the molded interconnect device is configured to be mounted to the printed circuit board.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the full benefit of U.S.Provisional Application Ser. No. 61/695,624, filed Aug. 31, 2012. Theentire contents of U.S. Provisional Application Ser. No. 61/695,624 areincorporated herein by reference.

The description relates to United States Published Application No.2012/0046514, filed Aug. 18, 2011, and titled “Implantable Blood Pump,”the entire contents of which are incorporated herein by reference.

FIELD

This description relates to mounting a sensor in a device, for example,mounting a Hall sensor in an implantable blood pump.

BACKGROUND

Ventricular assist devices, known as VADs, are implantable blood pumpsused for both short-term and long-term applications where a patient'sheart is incapable of providing adequate circulation. For example, apatient suffering from heart failure may use a VAD while awaiting aheart transplant. In another example, a patient may use a VAD whilerecovering from heart surgery. Thus, a VAD can supplement a weak heartor can effectively replace the natural heart's function. VADs can beimplanted in the patient's body and powered by an electrical powersource inside or outside the patient's body.

SUMMARY

The present disclosure describes one or more general aspects,implementations or embodiments involving devices, systems and methodsfor mounting a sensor in a device, for example, mounting a Hall sensorin an implantable blood pump.

When monitoring or controlling an electromagnetically levitated rotatingobject, it is useful to have sensors placed about the circumference ofthe rotating object to monitor its angular position, angular velocity,and any offsets from its ideal rotating axis. Placing these sensors canbe challenging from the perspective of locating each sensor axiallysymmetric to the other sensors and facilitating an assembly process thatdoes not impose mechanical stresses on the sensor package electricalinterconnects.

One or more of the following aspects of this disclosure can be embodiedalone or in combination as methods that include the correspondingoperations. One or more of the following aspects of this disclosure canbe implemented alone or in combination in a molded interconnect deviceor in an implantable blood pump that perform operations according to theone or more of the following aspects. One or more of the followingaspects of this disclosure can be implemented alone or in combination ina molded interconnect device or in an implantable blood pump thatincludes parts according to the one or more of the following aspects.

In aspect 1, a molded interconnect device carrying a Hall sensor fortransducing a position of a rotor of an implantable blood pump, themolded interconnect device is comprising: one or more integratedelectronic circuit traces configured to electrically connect the Hallsensor with a printed circuit board of the implantable blood pump,wherein the molded interconnect device is configured to be mounted tothe printed circuit board.

Aspect 2 according to aspect 1, wherein the molded interconnect devicefurther comprises: at least one recess on a surface of the device, thesurface being oriented towards the printed circuit board or facing theprinted circuit board.

Aspect 3 according to aspect 2, wherein the recess is configured to beat least partially filled with an adhesive.

Aspect 4 according to aspect 3, wherein the adhesive is configured tomount the molded interconnect device to the printed circuit board duringthe operation of the pump.

Aspect 5 according to any one of aspects 2 to 4, wherein the recess isadapted to be form-fit with a soldered joint that electrically connectsthe printed circuit board with the one or more integrated electroniccircuit traces of the molded interconnect device.

Aspect 6 according to any one of aspects 3 to 5, wherein the adhesive isapplied between the Hall sensor and the printed circuit board and/orbetween a surface of the device and the printed circuit board.

Aspect 7 according to any one of aspects 1 to 6, wherein the moldedinterconnect device is configured to be attached on the printed circuitboard between pole pieces of a stator of the pump.

Aspect 8 according to any one of aspects 1 to 7, wherein the Hall sensoris configured to output a voltage that is directly proportional to astrength of a magnetic field that is located in a proximity of polepieces of a stator of the pump and the rotor of the pump.

Aspect 9 according to an implantable blood pump, the pump comprising: ahousing defining an inlet opening and an outlet opening; a dividing wallwithin the housing defining a blood flow conduit, the blood flow conduitextending between the inlet opening and the outlet opening of thehousing; a rotary motor including a stator and a rotor, the stator beingdisposed within the housing circumferentially about the dividing wallsuch that the blood flow conduit extends through the stator, the statorbeing disposed circumferentially about at least a part of the rotor andbeing positioned relative to the rotor such that in use blood flowswithin the blood flow conduit through the stator before reaching therotor, and the rotor having permanent magnetic poles for magneticlevitation of the rotor; and a molded interconnect device carrying aHall sensor, the Hall sensor being configured to transduce a position ofthe rotor.

Aspect 10 according to aspect 9, wherein the molded interconnect deviceis mounted on a printed circuit board of the rotary motor between polepieces of the stator.

Aspect 11 according to any one of aspects 9 to 10, wherein the moldedinterconnect device comprises one or more integrated electronic circuittraces that are configured to electrically connect the Hall sensor withthe printed circuit board.

Aspect 12, combinable with any one of aspects 1 to 11 or with any one ofaspects 13 to 20, wherein the stator includes a first coil for drivingthe rotor and a second coil for adjusting a radial position of therotor, the first coil and the second coil being wound around one or moreof the pole pieces of the stator.

Aspect 13 according to any one of aspects 9 to 12, further comprising:at least one recess on a surface of the molded interconnect device, thesurface being oriented towards the printed circuit board or facing theprinted circuit board.

Aspect 14 according to aspect 13, wherein the recess is configured to beat least partially filled with an adhesive, and wherein the adhesive isadapted to secure the molded interconnect device to the printed circuitboard during operation of the pump after being applied between the Hallsensor and the printed circuit board and/or after being applied betweenthe surface of the molded interconnect device and the printed circuitboard.

Aspect 15 according to any one of aspects 13 to 14, wherein the recessis adapted to be form-fit with a soldered joint that electricallyconnects the printed circuit board with the one or more integratedelectronic circuit traces of the molded interconnect device.

Aspect 16 according to any one of aspects 9 to 15, wherein the Hallsensor is configured to output a voltage that is directly proportionalto a strength of a magnetic field that is located in a proximity of thepole pieces and the rotor of the pump.

Aspect 17 according to any one of aspects 1 to 16, further comprising:an active electromagnetic control system configured to radially centerthe rotor within a blood flow conduit if the position transduced by theHall sensor is outside a predefined volume within the blood flowconduit.

Aspect 18, combinable with any one of aspects 1 to 17, is a method ofassembling a blood pump, the method comprising: assembling a motorstator and control electronics in a housing circumferentially about aninternal dividing wall, the internal dividing wall defining the a bloodflow conduit that extends from an inlet opening to an outlet opening ofthe housing, the stator being assembled in the housing such that theblood flow conduit extends through the motor stator; disposing amagnetically-levitated rotor within the blood flow conduit andsurrounded by the stator such that impeller blades carried by the rotorare downstream of the rotor from the inlet opening, and such that, inuse, the impeller pumps blood from the inlet opening to the outletopening through the stator; mounting a molded interconnect devicebetween pole pieces of the motor stator onto a printed circuit board ofthe motor stator, wherein the molded interconnect device carries a Hallsensor that is configured to transduce a position of the rotor; andelectrically connecting the Hall sensor with the printed circuit boardand electrically connecting the printed circuit board with the controlelectronics.

Aspect 19 according to aspect 18, wherein the molded interconnect deviceis being placed on the printed circuit board by an insertion machine.

Aspect 20 according to any one of aspects 9 to 19, wherein the moldedinterconnect device is in accordance with any one of the aspects 1 to 8.

In aspect 21, a sensor mount assembly comprising: a printed circuitboard having rigid and flexible portions; sensors having rigid materialattached thereto; and a carrier for supporting the printed circuit boardand the sensors, the carrier having rails to locate the rigid materialattached to the sensors.

In aspect 22, an apparatus comprising: a circuit board having an outerregion, extensions, and end regions, the extensions each having a firstend coupled to the outer region, the extensions each extending inwardfrom the outer region to a second end that is coupled to one of the endregions, wherein the extensions are more flexible than the end regions;electrical interconnects disposed at the end regions; and a plurality ofsensors, each of the plurality of sensors being mounted to a respectiveelectrical interconnect disposed at one of the end regions.

Aspect 23 according to aspect 22, wherein the extensions are configuredto flex to direct stress away from the end regions.

Aspect 24 according to aspect 22 or 23, wherein the outer region is moreflexible than the end regions.

Aspect 25 according to any one of aspects 22 to 24, wherein the outerregion is generally circular, and the extensions extend radially inwardfrom the outer region.

Aspect 26 according to any one of aspects 22 to 25, wherein the outerregion defines a closed boundary around an opening defined through thecircuit board, and the extensions and end regions extend into theopening.

Aspect 27 according to any one of aspects 22 to 26, wherein the circuitboard has a generally planar surface, the electrical interconnects aredisposed at the generally planar surface, and the sensors extend fromthe generally planar surface.

Aspect 28 according to any one of aspects 22 to 27, wherein each of theextensions extends along a corresponding axis and each of the extensionshas a width perpendicular to the corresponding axis; and wherein the endregion located at the end of each extension has a width perpendicular tothe corresponding axis of the extension, the width of the end regionbeing greater than the width of the extension.

Aspect 29 according to any one of aspects 22 to 28, further comprising acarrier configured to attach to the circuit board and orient the sensorsin a predetermined alignment with respect to a motor assembly.

Aspect 30 according to aspect 29, further comprising a plurality ofguide members, each guide member being mounted to one of the sensors inthe plurality of sensors; wherein the carrier is configured to attach tothe circuit board and engage the guide members.

Aspect 31 according to aspect 29 or 30, wherein each of the guidemembers is located at an upper surface of one of the sensors in theplurality of sensors.

Aspect 32 according to any one of aspects 29 to 31, wherein each of theguide members is an electrically neutral circuit board segment.

Aspect 33 according to any one of aspects 29 to 32, wherein the carrierhas an inner region that connects each of the end regions when thecircuit board is received in the carrier, and the carrier hasprojections that extend outward from the inner region to the outerregion of the circuit board when the circuit board is received in thecarrier.

Aspect 34 according to any one of aspects 22 to 33, wherein theplurality of sensors comprise Hall effect sensors configured to detectmagnetic fields indicative of parameters of a motor of an implantableblood pump.

Aspect 35 according to any one of aspects 22 to 34, wherein the sensorsare configured to produce data indicative of a position of a rotor of animplantable blood pump.

Aspect 36 according to any one of aspects 22 to 35, wherein the sensorsare configured to output a voltage that is directly proportional to astrength of a magnetic field that is located in proximity to pole piecesof a motor stator and a rotor of an implantable blood pump.

Aspect 37 according to any one of aspects 22 to 36, wherein the sensorsare oriented axi-symmetrically.

In aspect 38, an implantable blood pump comprising the apparatus of anyone of aspects 22 to 37.

In aspect 39, A method comprising: mounting sensors to a circuit boardto form a sensor assembly; installing a mechanical carrier in a motorassembly, the mechanical carrier defining a predetermined alignment ofthe sensors with respect to the motor assembly; after installing themechanical carrier in the motor assembly, placing the circuit board ofthe sensor assembly in the mechanical carrier; and positioning thesensors in the mechanical carrier such that the sensors are arranged inthe predetermined alignment.

Aspect 40 according to aspect 39, wherein installing the mechanicalcarrier in the motor assembly comprises installing the mechanicalcarrier in a motor assembly of an implantable blood pump, the mechanicalcarrier defining a predetermined alignment of the sensors with respectto the motor assembly of the implantable blood pump.

Aspect 41 according to aspect 40, wherein mounting the sensors to thecircuit board comprises mounting the sensors to a circuit board that hasextensions that extend to end regions having electrical interconnectsdisposed at the end regions, the extensions being more flexible than theend regions electrically connecting the sensors to the electricalinterconnects.

Aspect 42 according to aspect 41, wherein positioning the sensors in themechanical carrier in the predetermined alignment comprises flexing theextensions of the circuit board such that the sensors are positioned inthe predetermined alignment within a predetermined tolerance.

Aspect 43 according to aspect 42, wherein flexing the extensionscomprises flexing the extensions to a greater degree than the endregions having the electrical interconnects.

Aspect 44 according to any one of aspects 39 to 43, wherein positioningthe sensors in the carrier in the predetermined alignment comprisespositioning the sensors axi-symmetrically.

Aspect 45 according to any one of aspects 39 to 44, wherein positioningthe sensors in the carrier in the predetermined alignment comprisespositioning the sensors in the carrier such that the sensors are locatedto detect one or more motor parameters of the blood pump.

Aspect 46 according to any one of aspects 39 to 45, wherein positioningthe sensors in the mechanical carrier in the predetermined alignmentcomprises placing the sensors in the mechanical carrier such that aguide member affixed to each sensor is received in a corresponding slotdefined by the mechanical carrier.

Aspect 47 according to any one of aspects 39 to 46, further comprisingaffixing a guide member to each sensor of the plurality of sensors.

Aspect 48 according to any one of aspects 39 to 47, further comprising,after positioning the sensors in the carrier in the predeterminedalignment, removing a portion of the circuit board that extends inwardbeyond the sensors.

Aspect 49 according to aspect 48, wherein removing a portion of thecircuit board comprises breaking off a portion of an end region along aperforated or scored line across the end region.

The following general aspects may be combinable with any one of theaspects 1 to 49.

In one general aspect, an implantable blood pump includes a housing anda blood flow conduit. Within the housing, the blood pump includes astator located about the blood flow conduit and a magnetically-levitatedrotor.

In another general aspect, an implantable blood pump includes a housingdefining an inlet opening and an outlet opening. Within the housing, adividing wall defines a blood flow conduit extending between the inletopening and the outlet opening of the housing. The blood pump has arotary motor that includes a stator and a rotor. The stator is disposedwithin the housing circumferentially about the dividing wall such thatthe inner blood flow conduit extends through the stator.

In another general aspect, an implantable blood pump includes apuck-shaped housing having a first face defining an inlet opening, aperipheral sidewall, and a second face opposing the first face. Theblood pump has an internal dividing wall defining an inner blood flowconduit extending between the inlet opening and an outlet opening of thehousing. The puck-shaped housing has a thickness from the first face tothe second face that is less than a width of the housing betweenopposing portions of the peripheral sidewall. The blood pump also has amotor having a stator and a rotor. The stator is disposed in the housingcircumferentially about the blood flow conduit and includes magneticlevitation components operable to control an axial position and a radialposition of the rotor. The rotor is disposed in the inner blood flowconduit and includes an impeller operable to pump blood from the inletopening to the outlet opening through at least a portion of the magneticlevitation components of the stator.

Implementations of the above aspects may include one or more of thefollowing features. For example, the stator is disposedcircumferentially about at least a part of the rotor and is positionedrelative to the rotor such that in use blood flows within the blood flowconduit through the stator before reaching the rotor. The rotor haspermanent magnetic poles for magnetic levitation of the rotor. A passivemagnetic control system is configured to control an axial position ofthe rotor relative to the stator, and an active electromagnetic controlsystem is configured to radially center the rotor within the inner bloodflow conduit. An electromagnetic control system controls at least one ofa radial position and an axial position of the rotor relative to thestator, and the electromagnetic control system has control electronicslocated within the housing about the dividing wall.

The control electronics are located between the inlet opening and thestator. The control electronics can be configured to control the activemagnetic control system. The rotor has only one magnetic moment. Thestator includes a first coil for driving the rotor and a second coil forcontrolling a radial position of the rotor, and the first coil and thesecond coil are wound around a first pole piece of the stator. Thehousing has a first face that defines the inlet opening, a second faceopposing the first face, and a peripheral wall extending from the firstface to the second face. The housing includes a rounded transition fromthe second face to the peripheral wall. The housing defines a volutelocated such that in use blood flows within the blood flow conduitthrough the stator before reaching the volute. The volute can be locatedbetween the stator and the second face. The housing can also include acap that includes the second face, defines at least part of the volute,and defines at least part of the outlet. The cap is engaged with theperipheral wall of the housing. The housing also includes an inletcannula extending from the first face and in fluid communication withthe inlet opening. The inlet cannula can be inserted into the patient'sheart. The outlet opening is defined in the second face and/or theperipheral wall. A thickness of the housing between the first face andthe second face is less than a width of the housing.

In another general aspect, a method includes inserting a puck-shapedblood pump housing into a patient's body. The blood pump is insertedsuch that an opening defined in a first flat face of the housing that isproximate to a stator of the blood pump faces the patient's heart.Additionally, the blood pump is inserted such that a second rounded faceof the housing that is proximate to an impeller of the blood pump facesaway from the patient's heart. The first face is disposed against aportion of the patient's heart such that the second face of the housingfaces away from the heart of the patient. In some implementations, themethod includes inserting an inlet cannula of the housing into thepatient's heart.

In another general aspect, making a blood pump includes assembling amotor stator and control electronics in a puck-shaped housingcircumferentially about an internal dividing wall. The internal dividingwall defines an inner blood flow conduit that extends from an inletopening to an outlet opening of the housing. The stator is assembled inthe housing such that the inner blood flow conduit extends through themotor stator. Disposed within the inner blood flow conduit is amagnetically-levitated rotor. The rotor is surrounded by the stator suchthat impeller blades carried by the rotor are downstream of the statorfrom the inlet opening. In use, the impeller pumps blood from the inletopening to the outlet opening through the stator.

Implementations may include one or more of the following features. Forexample, the rotor has only one magnetic moment. The stator includes atleast one first coil for driving the rotor and at least one second coilfor controlling a radial position of the rotor, the at least one firstcoil and the at least one second coil being wound around a first polepiece of the stator. The housing includes a first face that defines theinlet opening, and further comprising engaging an end cap with aperipheral wall of the housing, the end cap including a second face,defining at least part of a volute, and defining at least part of theoutlet opening. The housing includes a rounded transition from thesecond face to the peripheral wall. The housing further includes aninlet cannula extending from the first face and in fluid communicationwith the inlet opening. A thickness of the housing between the firstface and the second face is less than a width of the housing.

In another general aspect, a method of pumping blood includesmagnetically rotating a centrifugal pump impeller of a blood pump deviceto draw blood from a patient's heart through an inlet opening of ahousing of the blood pump device into an inner blood flow conduit withina stator in the housing, through the inner blood flow conduit, andthrough an outlet opening of the housing. The method includesselectively controlling a radial position of the impeller within theinner blood flow conduit.

In another general aspect, a sensor mount assembly includes a printedcircuit board having rigid and flexible portions, sensors having rigidmaterial attached thereto, and a carrier for supporting the printedcircuit board and the sensors. The carrier has rails to locate the rigidmaterial attached to the sensors.

The details of one or more of these and other aspects, implementationsor embodiments are set forth in the accompanying drawings and thedescription below. Other features, aims and advantages will be apparentfrom the description and drawings, and from the claims.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of a blood pump in a use position implanted ina patient's body.

FIG. 2 is a cross-sectional view of the blood pump of FIG. 1.

FIG. 3 is a partial cut-away perspective view of a stator of a bloodpump.

FIG. 4 is a bottom perspective view of a blood pump.

FIG. 5 is a top perspective view of the blood pump of FIG. 4.

FIG. 6 is a bottom perspective view and side perspective view of anexemplary sensor of FIG. 3.

FIG. 7 is a top perspective view and side perspective view of anexemplary sensor in bump design.

FIG. 8 is a top perspective view and side perspective view of anexemplary sensor in via design.

FIG. 9 is a top perspective view and side perspective view of anexemplary sensor in pocket design.

FIG. 10 is an illustration of an alternative embodiment of a sensormount.

FIG. 11 is a top view of a circuit board of the sensor mount of FIG. 10.

FIG. 12 is a cross-sectional view of the circuit board of FIG. 11 alongline 12-12.

FIG. 13 illustrates a break-away tab of the circuit board of FIG. 11.

FIG. 14 is a flow diagram illustrating a method of manufacturing asensor assembly.

Reference numbers and designations in the various drawings indicateexemplary aspects, implementations or embodiments of particular featuresof the present disclosure.

DETAILED DESCRIPTION

This description relates to mounting a sensor, such as a Hall sensor, inan implantable blood pump.

The subject matter described in this disclosure can be implemented inparticular aspects or embodiments so as to realize one or more of thefollowing advantages.

First, a molded interconnect device may allow a Hall sensor to bepositioned at an adequate position within the blood pump, while thedevice may be inserted into the pump with insertion machines employedfor the assembly of the pump. For example, the implementations oraspects described herein allow a Hall sensor to be positioned andmounted on a printed circuit board of a stator of the pump therebyallowing the Hall sensor to transduce a position of a rotor duringoperation of the pump.

Second, mechanical stress on integrated electronic conductive traces ofthe molded interconnect device may be reduced and may thereby enhancethe robustness of a connection between the device and a printed circuitboard. In general, particular aspects described herein may provideimproved robustness of the device carrying the Hall sensor on the boardand within the pump, e.g. for halt or break off test of the motor of thepump.

Third, the molded interconnect device carrying the Hall sensor may allowadhesives to be easily employed to further enhance the stability of theHall sensor in the pump.

Fourth, the force applied to a soldered joint between the printedcircuit board and the molded interconnect device during operation of thepump may be reduced, e.g. the force may a centrifugal force, a shearforce and/or a frictional force.

Other advantages of this disclosure will be apparent to those skilled inthe art.

With reference to FIGS. 1, 4 and 5, a left ventricular assist blood pump100 having a puck-shaped housing 110 is implanted in a patient's bodywith a first face 111 of the housing 110 positioned against thepatient's heart H and a second face 113 of the housing 110 facing awayfrom the heart H. The first face 111 of the housing 110 includes aninlet cannula 112 extending into the left ventricle LV of the heart H.The second face 113 of the housing 110 has a chamfered edge 114 to avoidirritating other tissue that may come into contact with the blood pump100, such as the patient's diaphragm. To construct the illustrated shapeof the puck-shaped housing 110 in a compact form, a stator 120 andelectronics 130 of the pump 100 are positioned on the inflow side of thehousing toward first face 111, and a rotor 140 of the pump 100 ispositioned along the second face 113. This positioning of the stator120, electronics 130, and rotor 140 permits the edge 114 to be chamferedalong the contour of the rotor 140, as illustrated in at least FIGS. 2,4, and 5, for example.

Referring to FIG. 2, the blood pump 100 includes a dividing wall 115within the housing 110 defining a blood flow conduit 103. The blood flowconduit 103 extends from an inlet opening 101 of the inlet cannula 112through the stator 120 to an outlet opening 105 defined by the housing110. The rotor 140 is positioned within the blood flow conduit 103. Thestator 120 is disposed circumferentially about a first portion 140 a ofthe rotor 140, for example about a permanent magnet 141. The stator 120is also positioned relative to the rotor 140 such that, in use, bloodflows within the blood flow conduit 103 through the stator 120 beforereaching the rotor 140. The permanent magnet 141 has a permanentmagnetic north pole N and a permanent magnetic south pole S for combinedactive and passive magnetic levitation of the rotor 140 and for rotationof the rotor 140. The rotor 140 also has a second portion 140 b thatincludes impeller blades 143. The impeller blades 143 are located withina volute 107 of the blood flow conduit such that the impeller blades 143are located proximate to the second face 113 of the housing 110.

The puck-shaped housing 110 further includes a peripheral wall 116 thatextends between the first face 111 and a removable cap 118. Asillustrated, the peripheral wall 116 is formed as a hollow circularcylinder having a width W between opposing portions of the peripheralwall 116. The housing 110 also has a thickness T between the first face111 and the second face 113 that is less than the width W. The thicknessT is from about 0.5 inches to about 1.5 inches, and the width W is fromabout 1 inch to about 4 inches. For example, the width W can beapproximately 2 inches, and the thickness T can be approximately 1 inch.

The peripheral wall 116 encloses an internal compartment 117 thatsurrounds the dividing wall 115 and the blood flow conduit 103, with thestator 120 and the electronics 130 disposed in the internal compartment117 about the dividing wall 115. The removable cap 118 includes thesecond face 113, the chamfered edge 114, and defines the outlet opening105. The cap 118 can be threadably engaged with the peripheral wall 116to seal the cap 118 in engagement with the peripheral wall 116. The cap118 includes an inner surface 118 a of the cap 118 that defines thevolute 107 that is in fluid communication with the outlet opening 105.

Within the internal compartment 117, the electronics 130 are positionedadjacent to the first face 111 and the stator 120 is positioned adjacentto the electronics 130 on an opposite side of the electronics 130 fromthe first face 111. The electronics 130 include circuit boards 131 andvarious components carried on the circuit boards 131 to control theoperation of the pump 100 by controlling the electrical supply to thestator 120. The housing 110 is configured to receive the circuit boards131 within the internal compartment 117 generally parallel to the firstface 111 for efficient use of the space within the internal compartment117. The circuit boards also extend radially-inward towards the dividingwall 115 and radially-outward towards the peripheral wall 116. Forexample, the internal compartment 117 is generally sized no larger thannecessary to accommodate the circuit boards 131, and space for heatdissipation, material expansion, potting materials, and/or otherelements used in installing the circuit boards 131. Thus, the externalshape of the housing 110 proximate the first face 111 generally fits theshape of the circuit boards 131 closely to provide external dimensionsthat are not much greater than the dimensions of the circuit boards 131.

With continued reference to FIG. 2 and with reference to FIG. 3, thestator 120 includes a back iron 121 and pole pieces 123 a-123 f arrangedat intervals around the dividing wall 115. The back iron 121 extendsaround the dividing wall 115 and is formed as a generally flat disc of aferromagnetic material, such as steel, in order to conduct magneticflux. The back iron 121 is arranged beside the control electronics 130and provides a base for the pole pieces 123 a-123 f.

Each of the pole piece 123 a-123 f is L-shaped and has a drive coil 125for generating an electromagnetic field to rotate the rotor 140. Forexample, the pole piece 123 a has a first leg 124 a that contacts theback iron 121 and extends from the back iron 121 towards the second face113. The pole piece 123 a may also have a second leg 124 b that extendsfrom the first leg 124 a through an opening 132 of a printed circuitboard 131 towards the dividing wall 115 proximate the location of thepermanent magnet 141 of the rotor 140. In an aspect, each of the secondlegs 124 b of the pole pieces 123 a-123 f is sticking through an opening132 of the printed circuit board 131. In an aspect, each of the firstlegs 124 a of the pole pieces 123 a-123 f is sticking through an opening132 of the printed circuit board 131. In an aspect, the openings 132 ofthe printed circuit board are enclosing the first legs 124 a of the polepieces 123 a-123 f.

In an aspect, at least one molded interconnect device 128 is mounted onthe printed circuit board of the pump 100, e.g. the at least one moldedinterconnect device 128 is mounted on the printed circuit board of thestator 120. In an aspect, the molded interconnect device 128 comprises aHall sensor 129, e.g., the molded interconnect device 128 carries theHall sensor 129. In some implementations, a magnetic sensor other than aHall sensor or another type of sensor may be used instead of the Hallsensor 129. For example, the molded interconnect device 128 may bemounted on the printed circuit board 131 via one or more of integratedelectric circuit traces, soldered joint and adhesive. For example, themolded interconnect device 128 may be mounted to the printed circuitboard 131 using an epoxy or liquid polymer crystals as the adhesive. Forinstance, the molded interconnect device 128 may be glued to the printedcircuit board 131.

In an aspect, the epoxy is a rapid curing, fast flowing, liquid epoxyfor use as capillary flow underfill on printed circuit boards, whereinwhen the epoxy is fully cured, it may reduce (e.g., minimize) inducedstress at solder joints between the printed circuit board 131 and themolded interconnect device 128. For example, the adhesive may improve athermal cycling performance of the printed circuit board 131, the moldedinterconnect device 128 and/or the soldered joints. In an aspect, theadhesive provides the functionality of an underfill between the printedcircuit board 131 and the at least one molded interconnect device 128.For example, the adhesive may be applied (e.g., as underfill) betweenthe Hall sensor 129 and the printed circuit board 131 and/or between theprinted circuit board 131 and the molded interconnect device 128.

In a general aspect, the Hall sensor 129 may be configured to transducea position of the rotor 140 of the pump 100. For example, the Hallsensor 129 may be in upright position on the printed circuit board 131.For instance, the Hall sensor 129 may be standing orthogonally on theprinted circuit board 131. For example, a longest edge of the Hallsensor 129 may be aligned to possess an orthogonal component withrespect to the surface of the printed circuit board 131. In a generalaspect, the Hall sensor 129 may be adapted to sense a position of therotor 140 of the pump 100. For example, the Hall sensor 129 may providean output voltage, which is directly proportional to a strength of amagnetic field that is located in between at least one of the polepieces 123 a-123 f and the permanent magnet 141. For example, the Hallsensor 129 may provide an output voltage, which is directly proportionalto a strength of a magnetic field that is located in a proximity of atleast one of the pole pieces 123 a-123 f and the rotor 140 of the pump100. For example, the Hall sensor 129 may provide an output voltage,which is directly proportional to a strength of a magnetic field that islocated in between at least one of the pole pieces 123 a-123 f and thepermanent magnet 141, and wherein the output voltage is directlyproportional to a current flowing in the Hall sensor 129.

In a general aspect, the Hall sensor 129 may provide an output voltage,which is directly proportional to a strength of a magnetic field that islocated in between at least one of the pole pieces 123 a-123 f and thepermanent magnet 141, and the output voltage may provide feedback to thecontrol electronics 130 of the pump 100 to determine if the rotor 140and/or the permanent magnet 141 is not at its intended position for theoperation of the pump 100. For example, a position of the rotor 140and/or the permanent magnet 141 may be adjusted, e.g. the rotor 140 orthe permanent magnet 141 may be pushed or pulled towards a center of theblood flow conduit 103 or towards a center of the stator 120.

Each of the pole pieces 123 a-123 f also has a levitation coil 127 forgenerating an electromagnetic field to control the radial position ofthe rotor 140. Each of the drive coils 125 and the levitation coils 127includes multiple windings of a conductor around the pole pieces 123a-123 f. Particularly, each of the drive coils 125 is wound around twoadjacent ones of the pole pieces 123, such as pole pieces 123 d and 123e, and each levitation coil 127 is wound around a single pole piece. Thedrive coils 125 and the levitation coils 127 are wound around the firstlegs of the pole pieces 123, and magnetic flux generated by passingelectrical current though the coils 125 and 127 during use is conductedthrough the first legs and the second legs of the pole pieces 123 andthe back iron 121. The drive coils 125 and the levitation coils 127 ofthe stator 120 are arranged in opposing pairs and are controlled todrive the rotor and to radially levitate the rotor 140 by generatingelectromagnetic fields that interact with the permanent magnetic poles Sand N of the permanent magnet 141. Because the stator 120 includes boththe drive coils 125 and the levitation coils 127, only a single statoris needed to levitate the rotor 140 using only passive and activemagnetic forces. The permanent magnet 141 in this configuration has onlyone magnetic moment and is formed from a monolithic permanent magneticbody 141. For example, the stator 120 can be controlled as discussed inU.S. Pat. No. 6,351,048, the entire contents of which are incorporatedherein for all purposes by reference. The control electronics 130 andthe stator 120 receive electrical power from a remote power supply via acable 119 (FIG. 1). Further related patents, namely U.S. Pat. No.5,708,346, U.S. Pat. No. 6,053,705, U.S. Pat. No. 6,100,618, U.S. Pat.No. 6,879,074, U.S. Pat. No. 7,112,903, U.S. Pat. No. 6,278,251, U.S.Pat. No. 6,278,251, U.S. Pat. No. 6,249,067, U.S. Pat. No. 6,222,290,U.S. Pat. No. 6,355,998 and U.S. Pat. No. 6,634,224, are incorporatedherein for all purposes by reference in their entirety.

The rotor 140 is arranged within the housing 110 such that its permanentmagnet 141 is located upstream of impeller blades in a location closerto the inlet opening 101. The permanent magnet 141 is received withinthe blood flow conduit 103 proximate the second legs 124 b of the polepieces 123 to provide the passive axial centering force thoughinteraction of the permanent magnet 141 and ferromagnetic material ofthe pole pieces 123. The permanent magnet 141 of the rotor 140 and thedividing wall 115 form a gap 108 between the permanent magnet 141 andthe dividing wall 115 when the rotor 140 is centered within the dividingwall 115. The gap 108 may be from about 0.2 millimeters to about 2millimeters. For example, the gap 108 is approximately 1 millimeter. Thenorth permanent magnetic pole N and the south permanent magnetic pole Sof the permanent magnet 141 provide a permanent magnetic attractiveforce between the rotor 140 and the stator 120 that acts as a passiveaxial centering force that tends to maintain the rotor 140 generallycentered within the stator 120 and tends to resist the rotor 140 frommoving towards the first face 111 or towards the second face 113. Whenthe gap 108 is smaller, the magnetic attractive force between thepermanent magnet 141 and the stator 120 is greater, and the gap 108 issized to allow the permanent magnet 141 to provide the passive magneticaxial centering force having a magnitude that is adequate to limit therotor 140 from contacting the dividing wall 115 or the inner surface 118a of the cap 118. The rotor 140 also includes a shroud 145 that coversthe ends of the impeller blades 143 facing the second face 113 thatassists in directing blood flow into the volute 107. The shroud 145 andthe inner surface 118 a of the cap 118 form a gap 109 between the shroud145 and the inner surface 118 a when the rotor 140 is levitated by thestator 120. The gap 109 is from about 0.2 millimeters to about 2millimeters. For example, the gap 109 is approximately 1 millimeter.

As blood flows through the blood flow conduit 103, blood flows through acentral aperture 141 a formed through the permanent magnet 141. Bloodalso flows through the gap 108 between the rotor 140 and the dividingwall 115 and through the gap 109 between the shroud 145 and the innersurface 108 a of the cap 118. The exemplary gaps 108 and 109 are largeenough to allow adequate blood flow to limit clot formation that mayoccur if the blood is allowed to become stagnant. The gaps 108 and 109are also large enough to limit pressure forces on the blood cells suchthat the blood is not damaged when flowing through the pump 100. As aresult of the size of the gaps 108 and 109 limiting pressure forces onthe blood cells, the gaps 108 and 109 are too large to provide ameaningful hydrodynamic suspension effect. That is to say, the blooddoes not act as a bearing within the exemplary gaps 108 and 109, and therotor is only magnetically-levitated. In various embodiments, the gaps108 and 109 are sized and dimensioned so the blood flowing through thegaps forms a film that provides a hydrodynamic suspension effect. Inthis manner, the rotor can be suspended by magnetic forces, hydrodynamicforces, or both.

Because the exemplary rotor 140 is radially suspended by active controlof the levitation coils 127 as discussed above, and because the rotor140 is axially suspended by passive interaction of the permanent magnet141 and the stator 120, no rotor levitation components are neededproximate the second face 113. The incorporation of all the componentsfor rotor levitation in the stator 120 (i.e., the levitation coils 127and the pole pieces 123) allows the cap 118 to be contoured to the shapeof the impeller blades 143 and the volute 107. Additionally,incorporation of all the rotor levitation components in the stator 120eliminates the need for electrical connectors extending from thecompartment 117 to the cap 118, which allows the cap to be easilyinstalled and/or removed and eliminates potential sources of pumpfailure.

In use, the drive coils 125 of the stator 120 generates electromagneticfields through the pole pieces 123 that selectively attract and repelthe magnetic north pole N and the magnetic south pole S of the rotor 140to cause the rotor 140 to rotate within stator 120. For example, theHall sensor 129 may sense a current position of the rotor 140 and/or thepermanent magnet 141, wherein the output voltage of the Hall sensor 129may be used to selectively attract and repel the magnetic north pole Nand the magnetic south pole S of the rotor 140 to cause the rotor 140 torotate within stator 120. As the rotor 140 rotates, the impeller blades143 force blood into the volute 107 such that blood is forced out of theoutlet opening 105. Additionally, the rotor draws blood into pump 100through the inlet opening 101. As blood is drawn into the blood pump byrotation of the impeller blades 143 of the rotor 140, the blood flowsthrough the inlet opening 101 and flows through the control electronics130 and the stator 120 toward the rotor 140. Blood flows through theaperture 141 a of the permanent magnet 141 and between the impellerblades 143, the shroud 145, and the permanent magnet 141, and into thevolute 107. Blood also flows around the rotor 140, through the gap 108and through the gap 109 between the shroud 145 and the inner surface 118a of the cap 118. The blood exits the volute 107 through the outletopening 105.

FIG. 6 describes a bottom and side view of an exemplary moldedinterconnect device 128 according to an aspect described herein. Themolded interconnect device 128 may carry the Hall sensor 129 on onesurface of the molded interconnect device 128, wherein the Hall sensormay be electrically connected with the molded interconnect device 128via one or more integrated electronic circuit traces 133. In an aspect,the Hall sensor 129 may be located inside the device 128 or may bepartially enclosed by the device 128. The bottom of the moldedinterconnect device 128 is facing the bottom side of the pump 100. Thetop of the molded interconnect device 128 is facing the printed circuitboard 131 of the pump 100. The bottom perspective of the moldedinterconnect device is illustrated in FIG. 6 (lower illustration). Themolded interconnect device 128 may possess a cut-out 128 a, wherein filmgate material may be removed. In an aspect, a thickness 128 b of wallsof the molded interconnect device 128 may be adapted for the moldedinterconnect device 128 to be aligned on the printed circuit board 131with an automated assembly machine, wherein the automated assemblymachine may also be used to assemble the printed circuit board 131and/or the stator 120 of the pump 100. For example, the thickness 128 bmay be below 1 millimeter, preferentially about 0.7 millimeters.

In a general aspect, to make the molded interconnect device 128 morerobust one or more of the followings actions are taken. An adhesive(e.g. an underfill material) is applied between the Hall sensor 129 anda surface of the molded interconnect device 128 and/or between a surfaceof the molded interconnect device 128 and the printed circuit board 131.This particular aspect or implementation may limit force flow throughthe integrated circuit traces and rather leads the forces directlythrough the adhesive into the printed circuit board 131. Additionallyand in an example, the adhesive may be easily implemented with theprinted circuit board assembly and manufacturing process. In a furtheraspect, the molded interconnect device 128 may be designed with recesses(e.g., pockets) that enable a form fit between the molded interconnectdevice 128 and soldered joints of the printed circuit board 131. In anaspect, laser parameters for structuring the molded interconnect device128 may be optimized and a width of the integrated electronic circuittraces may be increased. In general, in blood pumps, mechanical forcesmay be generated due to thermal expansion and metallized traces orjoints may become separated from their supporting material, wherein themetallized traces may experience a fracture during pump operation. In ageneral aspect, halt tests and/or break off tests of the motor wereperformed and rendered one or more of the following designs of themolded interconnect device 128 particularly mechanically robust duringoperation of the pump.

FIG. 7 describes an exemplary top and side view of a Hall sensor in abump design according to one or more aspects of the present disclosure.The molded interconnect device 128 carries a Hall sensor 129 andincludes multiple integrated electronic circuit traces 133, wherein oneor more bumps 136 may be added to the traces 133. This particular aspectmay reduce mechanical stress on the traces 133, e.g., by using amechanical form fit. In an aspect, the size of the bump 136 may be below1 millimeters, preferentially 0.73 millimeters. For example, the moldedinterconnect device 128 may include four bumps 136 that are located ateach corner of one surface of the device 128, wherein the surface isfacing the printed circuit board 131 when the device 128 is mounted onthe printed circuit board 131.

FIG. 8 describes an exemplary top and side view of a Hall sensor in avia design according to one or more aspects of the present disclosure.The molded interconnect device 128 carries a Hall sensor 129 andincludes one or more integrated electronic circuit traces 133, whereinone or more electrically conductive pins 134 may each include at leastone via 134 a. In an example, the pins 134 may be a part of the traces133. This particular implementation may increase a strength of theconnection between the traces 133 and the molded interconnect device 128by implementing the via 134 a that may extend through a wall of thedevice 128. For example, the via 134 a is a hole or a hollow channelextending through the wall of the molded interconnect device 128. Forexample, the pins 134 may be soldered to the printed circuit board 131thereby electrically connecting the Hall sensor 129 with the circuitboard 131.

FIG. 9 describes an exemplary top and side view of a Hall sensor in apocket design according to one or more aspects of the presentdisclosure. The molded interconnect device 128 carries a Hall sensor 129and includes one or more integrated electronic circuit traces 133,wherein one or more electrically conductive recesses 135 or pockets 135may be located at one or more surfaces of the device 128. For example,the recess or pocket 135 may be an electrically conductive pin that isformed by a cut-out of a wall of the device 128. For instance, therecess or pocket 135 may be formed by cutting-out a fraction of a wallof the molded interconnect device 128. For instance, the fraction may becut out at a corner of the device 128, wherein the corner is facing theprinted circuit board 131 when the device 128 is mounted on the circuitboard 131. In an aspect, the width 135 b of the recess 135 may be lessthan 1 millimeter, preferentially 0.6 millimeter. In an aspect, thelength 135 a of the recess 135 may be less than 1 millimeter,preferentially 0.8 millimeter. In an aspect, the height of the recess135 may be less than 1 millimeter. In an aspect, the molded interconnectdevice is wedge- or trapeze-shaped with an apex angle 128 c between 10and 45 degrees, preferentially 25 degrees or 30 degrees.

In an aspect, the recess or pocket 135 may be form-fit with solderedjoints, the soldered joints electrically and/or mechanically connectingthe printed circuit board 131 with the integrated electronic circuittraces 133 of the molded interconnect device 128. For example, eachrecess or pocket 135 of the device 128 may at least partially enclose asoldered joint, the soldered joints electrically and/or mechanicallyconnecting the printed circuit board 131 with the integrated electroniccircuit traces 133 of the molded interconnect device 128. In an aspect,the recess or pocket 135 may be at least partially filled with anadhesive, which mounts the device 128 to the printed circuit board 131and secures mounting of the molded interconnect device 128 to theprinted circuit board 131 of the pump 100 during operation of the pump100. The adhesive (e.g., a liquid epoxy) may be configured to performcapillary actions on the circuit board 131 and flows into the recess orpocket 135 without an additional external force applied to the adhesive.The particular implementation described herein may remove forces appliedto the traces 133 and/or the soldered joints during operation of thepump 100 and may guide these forces between the device 128 and thecircuit board 131 through the adhesive (e.g. underfill), wherein theforces may for example be centrifugal forces, shear forces and/orfrictional forces.

The particular implementation of the pocket design described in thecontext of FIG. 9 may reduce mechanical stress on the traces 133 of themolded interconnect device 128 and may thereby enhance the robustness ofa connection between the device 128 and the board 131. The particularimplementation of the pocket design described herein may increase thestability of the integrated electronic circuit traces 133 of the moldedinterconnect device 128. The particular implementation of the pocketdesign described herein may increase the stability of the connectionbetween the integrated electronic circuit traces 133 and the moldedinterconnect device 128. The particular implementation of the pocketdesign described herein may reduce the force applied to the integratedelectronic circuit traces 133 of the molded interconnect device 128,e.g. the force may a centrifugal force, a shear force and/or africtional force that may occur during operation of the implantableblood pump 100. The particular implementation of the pocket designdescribed in the context of FIG. 9 may reduce the force applied to thesoldered joint between the printed circuit board 131 and the moldedinterconnect device 128, e.g. the force may a centrifugal force, a shearforce and/or a frictional force that may occur during operation of theimplantable blood pump 100. In general, the particular implementationsor aspects described in FIGS. 7, 8 and 9 may provide improved robustnessof the device 128 on the board 131 within the pump 100, e.g. therobustness may be determined or classified by a halt or break off testof the motor of the pump 100.

In a general aspect, using silicone coating in a proximity of the moldedinterconnect device 128 on the printed circuit board 131 may be a bufferand may reduce mechanical stress on the device 128 and/or the Hallsensor 129.

In a general aspect, the width of the integrated electronic circuittraces 133 may be 0.2-0.25 millimeters. In an aspect, lead-free soldermay be applied between the Hall sensor 129 and the molded interconnectdevice 128. In an aspect, the molded interconnect device 128 is directlysoldered on the printed circuit board 131 of the pump 100.

Referring to FIGS. 10 and 11, another implementation of a sensor mount200 includes a printed circuit board 202, sensors 208, and a mechanicalcarrier 210. FIG. 10 illustrates the sensor mount 200 assembly as itwould be configured within an assembled blood pump. FIG. 11 illustratesthe circuit board 202 and sensors 208 before the circuit board 202 andsensors 208 are placed in the carrier 210 during assembly of the bloodpump.

The printed circuit board 202 has rigid portions 204, and also hasflexible portions 206 that provide mechanical compliance betweenindividual sensors 208 while maintaining a single set of solderedelectrical interconnects between the sensors 208 and the remainder ofthe system. The circuit board 202 can be, for example, a rigid-flexcircuit board. Because there is compliance in the flexible portions 206,mechanical positioning tolerances in the mechanical fixtures can beaccommodated without placing excessive stress on the electricalinterconnects.

The sensors 208 can be soldered to the circuit board 202 while thecircuit board 202 is flat and unstrained. During assembly of the pumpmotor assembly, the circuit board 202 is positioned on top of a carrier210, which may already be installed in the motor assembly. The carrier210 has guide rails 212 that orient the sensors 208 soldered to thecircuit board 202. When installing the sensors 208 into the carrier 210,the flexible portions 206 of the circuit board 202 flex to permit thesensors 208 to be positioned in a precise alignment within the motorassembly.

As shown in FIG. 11, the circuit board 202 is generally planar and hasan outer region 220. In some implementations, the outer region 220 isgenerally circular or ring-shaped. The outer region 220 defines an outerperimeter 221 that bounds an opening 222 defined through the center ofthe circuit board 202. The opening 222 can be located and sized to admitportions of a blood flow conduit, a pump motor stator, a pump housing,and/or a rotor through the circuit board 202 in an assembled pump.

The circuit board 202 includes extensions 230 that project inward fromthe outer region 220 into the opening 222. Each extension 230 may extendlinearly along a corresponding longitudinal axis 239, for example, in adirection radially inward from the outer region 220. In someimplementations, the extensions 230 are positioned around the interiorof the outer region 220 such that there are spacings or gaps 231 betweenthe extensions 230. In an assembled pump, a portion of the motor stator,such as a pole piece, drive coil, levitation coil, or other component,may be positioned in each of the gaps 231 between extensions 230. Eachextension 230 has an outer end 232 and an inner end 234. The outer ends232 are fixed to the outer region 220, and each inner end 234 is fixedto an end region 240.

The end regions 240 are free ends, which are not attached to the rest ofthe circuit board 202 except at the inner ends 234 of the respectiveextensions 230. Each end region 240 has electrical interconnects 250(e.g., exposed pads) disposed at the surface of the end region 240 (seeFIG. 13). Each of the end regions 240 can have a sensor 208 connectedelectrically and mechanically to the end region 240. Circuit traces,wires, or other conductive elements (not shown) can extend along theextensions 230 to connect the electrical interconnects 250 to othercircuitry of the circuit board 202 and other pump control electronics.

In some implementations, the width, W₁, of an end region 240 is greaterthan the width, W₂, of the extension 230. The widths W₁, W₂ can bemeasured perpendicular to the longitudinal axis 239 of the extension230. In some implementations, the end regions 240 extend perpendicularto the longitudinal axis 239 of the extensions 230 beyond one or bothlateral edges 236, 238 of the extensions 230.

The extensions 230 are connected through the outer region 220, but thecircuit board 202 does not otherwise connect the extensions 230 to eachother. Because the extensions 230 extend freely from the outer region220 in, for example, a cantilevered fashion, each extension 230 can flexindependently of the other extensions 230 to allow positioning of thesensors 208 located at the end regions 240.

The outer region 220 and the extensions 230 are more flexible than theend regions 240. The rigidity of the end regions 240 limits the riskthat a connection between the sensors 208 and the electricalinterconnects 250 may fail due to excessive stress or flexion on the endregions 240. When the sensors 208 are positioned with respect to themotor stator, forces on the sensors 208 cause flexion of the extensions230 while causing less flexion in the more rigid end regions 240 wherethe electrical interconnects 250 are located.

The higher rigidity of the end region 240 may be achieved by using adifferent material or structure than is used to form the outer region220 and extensions 230. In addition, or as an alternative, the higherrigidity of the end regions 240 may be achieved by adding areinforcement layer or other member to the end regions 240.

Referring to FIG. 12, the outer region 220 and extensions 230 can beinclude a flexible dielectric material, such as a polyimide, e.g.,Kapton. For example, the outer region 220 includes a flexible dielectriclayer 304 formed of, for example, polyimide, located between metallayers 302 formed of, for example, copper. A polyimide film 312 or othercoating may be applied to the metal layers 302. In some implementations,the metal layers 302 are exposed at an outer edge of the outer region220 to provide electrical connectivity.

The extensions 230 include an additional flexible dielectric layer 304 aformed of, for example, polyimide, and an additional metal layer 302 a.A layer of adhesive 310 can bond the flexible dielectric layer 304 a toone of the metal layers 302. The layers of the extensions 230 can form aflexible core 320 that extends through the end regions 240. The metallayers 302, 302 a of the extensions 230 may also be covered with apolyimide film 312 or other coating. The outer region 220, whichincludes fewer layers than the extensions 230, can be more flexible thanthe extensions 230.

The flexible dielectric layers 304, 304 a may include polyimide, asdiscussed above. Other suitable dielectric materials include thoseindicated in industry standard guideline document IPC-4202. For example,the flexible dielectric layers 304, 304 a may include polyvinylfluoride(PVF), polyethylene terephthalate polyester (PET), fluorinatedethylene-propylene copolymer (FEP), polytetrafluorethylene (PTFE),aramid, polyamide-imide, epoxy, polyetherimide, polysulfone,polyethylene naphthalate (PEN), and/or thermotropic liquid crystalpolymer.

The end regions 240 can be constructed of a laminate material builtaround the flexible core 320. For example, the end regions 240 includethe flexible core 320 and rigid dielectric layers 306 located above andbelow the flexible core. The rigid dielectric layers 306 may be formedof, for example, an epoxy-impregnated glass laminate, such as FR-4.Various other laminates and materials may be used, including epoxylaminates including glass, cellulose, aramid fiber, and/or fiberglass,where the materials in the laminate may be woven or non-woven. Othersuitable materials are indicated in industry standard guideline documentIPC-4101. The end regions 240 also include metal layers 302 b located onthe rigid dielectric layers 306, and solder mask layers 308 located overthe metal layers 302 b.

In the example shown in FIGS. 10-13, there are eight extensions 230, anda sensor 208 is mounted at the end region 240 of each extension 230. Thesensors 208 can be Hall effect sensors or other appropriate magneticsensors. The sensors 208 can be oriented axi-symmetrically, for example,about an axis through the center of the opening 222 extendingperpendicular to the circuit board 202. For example, the sensors 208 canbe positioned at equal angular offsets from the nearest sensors 208 oneither side, and each sensor 208 can be oriented to face toward thecenter of the opening 222.

As discussed above, one or more of the sensors may be Hall effectsensors configured to detect magnetic fields indicative of parameters ofa motor of an implantable blood pump. The sensors can be configured tooutput a voltage that is directly proportional to the strength of amagnetic field that is located in proximity to pole pieces of a motorstator and/or a rotor of an implantable blood pump. In someimplementations, the sensors are configured to produce data indicativeof a position of a rotor of an implantable blood pump.

Referring again to FIG. 10, after the sensors 208 are mounted to thecircuit board 202, the circuit board 202 and sensors 208 are placed in amechanical carrier 210. The assembly of the circuit board 202 andsensors 208 may be inserted in the carrier 210 by moving the sensoryassembly downward along an axis, for example, along arrow A, so that thecircuit board rests against an upper surface of the carrier 210. Thecarrier 210 can be more rigid than the circuit board 202, and can beformed of, for example, plastic or metal. In some implementations, thecarrier 210 is affixed to the pump housing or motor assembly prior toinsertion of the circuit board 202 and sensors 208. The carrier 210 maybe mechanically integral to the motor assembly.

In an assembled blood pump, the carrier 210 acts as a precision fixtureand as a mechanical support for the sensors 208. During manufacturing,the sensors 208 are soldered to the circuit board 202 while the circuitboard 202 is flat and unstrained. Due to the various tolerances infabrication and soldering, there may exist some uncertainty about theexact location of the sensors 208 after attachment to the circuit board202. During final motor assembly, the circuit board 202, with sensors208 already attached, is placed on top of the carrier 210. The machiningor fabrication of the carrier 210 can be performed more precisely thanthe soldering of the sensors 208. As a result, the carrier 210 canprecisely orient the sensors 208 relative to each other and relative tothe rest of the motor assembly.

The carrier 210 has an inner region 252 that connects each of the endregions 240 within the opening 222. The inner region 252 can begenerally circular. The carrier 210 has projections 254 that extendoutward from the inner region 252. The circuit board 202, with solderedsensors 208, is received in the carrier 210 with the circuit board 202in a substantially flat orientation. Each projection 254 of the carrier210 receives one of the extensions 230 of the circuit board 202 in agroove 255. The projections 254 are wider than the extensions 230 andextend beyond the lateral edges 236, 238 of the extensions 230. Theprojections 254 extend from the inner region 252 to the outer region 220of the circuit board 202. In some implementations, the carrier 210 hasan outer region that is generally circular or ring-shaped that connectsthe projections 254. In some implementations, the spacings or gaps 231are defined between the projections 254. In an assembled pump, a portionof the motor stator, such as a pole piece, drive coil, levitation coil,or other component, may be positioned in the gaps 231 between theprojections 254.

The carrier 210 includes features that orient the sensors 208 in apredetermined alignment or orientation with respect to each other andwith respect to the pump motor assembly. Each projection 254 of thecarrier 210 includes guide rails 212 that can be used to align a sensor208. Each pair of guide rails 212 defines a space or slot 257 in whichto receive a sensor 208. When the circuit board 202 and sensors 208 arepositioned in the carrier 210, the guide rails 212 extend along oppositesides of the end regions 240. The guide rails 212 define slots 256 thatreceive guide members 214 attached to the sensors 208. When the circuitboard 202 is received in the carrier 210, the slots 256 extend generallyperpendicular to the longitudinal axes 239 of the correspondingextensions 230. The slots 256 also extend substantially perpendicular tothe planar surface of the circuit board 202.

The sensors 208 are appropriately positioned with respect to the rest ofthe motor assembly when the sensors 208 are located in the slots 257 andthe guide members 214 are located in the slots 256. In this alignment,the sensors 208 may be located to, for example, to detect parameters ofthe pump's motor.

To facilitate positioning of the sensors 208, a guide member 214 isattached to the top surface of each sensor 208. The engagement of theguide members 214 with the guide rails 212 of the carrier 210 can alignthe sensors 208 relative to each other and relative to the rest of themotor assembly, e.g., pole pieces, levitation coils, drive coils, andother motor stator components. The guide members 214 can be electricallyneutral rigid PCB portions. Each guide member 214 extends generallyperpendicular to the longitudinal axis 239 of the extension 230 to whichthe sensor 208 is attached. The guide member 214 extends beyond theedges of the sensor 208, in a direction perpendicular to thelongitudinal axis 239 of the extension 230, to engage the slots 256 inthe guide rails 212. The guide member 214 may extend to or beyond theedges of the end regions 240.

The guide members 214 allow a person or machine assembling the sensorunit to grasp the guide member 214 and thereby manipulate the attachedsensor 208 without causing mechanical damage to the sensor 208. Inaddition, the guide members 214 can be masked with a static dissipativecoating that minimizes the risk of damage to the circuitry of thesensors 208 due to electrostatic discharge (ESD).

Referring to FIGS. 11 and 13, in some implementations, the circuit board202 is initially formed with excess portions or break-away tabs 216 aspart of the end regions 240. The tabs 216 can be formed of the samematerial as the region where the electrical interconnects are located,for example, a material more rigid than the material that forms theextensions 230. While attached to the circuit board 202, the tabs 216can be used to position or otherwise hold the circuit board 202. Thetabs 216 can be coated with a static electricity dissipating film toprotect the sensors 208 and other components during handling.

After the sensors 208 are soldered to the end regions 240, the tabs 216may be removed (e.g., by breaking the tabs 216 off from the remainder ofthe end region 240), leaving a minimum amount of rigid PCB material tosupport the sensors 208 and resulting in an overall smaller assembly.FIG. 10 shows the circuit board 202 after the tabs 216 have beenremoved.

Referring to FIG. 13, the tab 216 is removed through the use ofcarefully positioned “break-away” scoring marks 218 and/or small slotsor holes commonly called “mouse bites.” These features provide a way ofprecisely locating the break-away transition and, during the break-awayprocess, imparting minimum stress on the soldered electricalinterconnects 250 joining the sensor 208 to the remaining rigid PCBportion.

Referring to FIG. 14, a method 400 for manufacturing an implantableblood pump can include mounting sensors 208 to a circuit board 202 toform a sensor assembly (402). The sensors 208 are mounted at regions ofthe circuit board 202, such as the end regions 240, that are more rigidthan adjacent regions of the circuit board 202, such as the extensions230. The sensors 208 can be soldered or otherwise assembled to thecircuit board 202 while the circuit board 202 is in a flatconfiguration, separate from the carrier 210 and the rest of the pump.

A mechanical carrier 210 is installed in the pump motor assembly (404).For example, the carrier 210 may be attached to one or more otherportions of a motor stator or pump housing. The carrier 210 defines apredetermined alignment for the sensors 208 to be located with respectto each other and the other components of the motor. The carrier 210 maybe installed so that portions of the motor stator, such as pole pieces,drive coils, levitation coils, or other components, are positioned ingaps 231 between projections 254 of the carrier 210.

After the mechanical carrier 210 is installed in the motor assembly, thecircuit board 202 of the sensor assembly is placed in the carrier 210(406). The circuit board 202 and the attached sensors 208 are placedover the top of the carrier 210. The circuit board 202 may be seatedagainst the carrier 210 by, for example, moving the circuit board 202downward against an upper surface of the carrier 210. The circuit board202 is received in the carrier 210, for example, with each projection254 of the carrier 210 receiving one of the extensions 230 in a groove255. The circuit board 202 may be in a generally planar orientation whenlocated in the carrier 210.

The sensors 208 are positioned in the carrier 210 (408). The carrier 210orients the sensors 208 so that the sensors 208 are in the predeterminedalignment with respect to the motor assembly for, for example, sensingmotor parameters. The individual sensors 208 are mechanically positionedbetween the guide rails 212 using the tabs 216 shown in FIG. 13. Placingthe circuit board 202 in the carrier 210 may involve flexing theextensions 230 and/or the outer region 220 of the circuit board 202 toprecisely locate the sensors 208 relative to each other and relative tothe rest of the motor assembly. For example, the carrier 210 canposition the sensors 208 in an arrangement for detecting magnetic fieldsindicative of parameters of a pump motor. In some implementations, thecarrier 210 aligns the sensors 208 axi-symmetrically. To position thesensors 208 in the carrier 210, the body of the sensor 208 can be placedin one of the slots 257, and the guide members 214 can be placed in theslots 256.

In some implementations, positioning the sensors 208 includes flexingthe extensions 230 of the circuit board 202 such that the sensors 208achieve a predetermined alignment within a predetermined tolerance.During motor assembly, for example, when positioning the sensors 208,the extensions 230 can flex to a greater degree than the end regions 240where the electrical interconnects 250 are located.

In some implementations, after the circuit board 202 and sensors 208 areinstalled in the carrier 210, portions of the circuit board 202 thatextend inward beyond the sensors 208 are removed. For example, aportion, such as a tab 216, of one or more of the end regions 240 may bebroken off along a perforated or scored line across the end region 240.

In some implementations, the method 300 includes affixing a guide member214 to each sensor 208, for example, at a top surface or edge oppositethe region where electrical contacts of the sensor 208 are located. Thesensor 208 is then manipulated by grasping the guide member 214.

A number of implementations have been described. Nevertheless, it willbe understood that various modifications may be made without departingfrom the spirit and scope of the claimed invention. For example, the cap118 can be engaged with the peripheral wall 116 using a differentattachment mechanism or technique, including snap-fit engagement,adhesives, or welding. Additionally, while the cap 118 has beendescribed as defining the outlet opening 105 and the chamfered edge 114,the outlet opening 105 and/or the chamfered edge 114 can be defined bythe peripheral wall 116 or by both the peripheral wall 116 and the cap118. Similarly, the dividing wall 115 can be formed as part of the cap118.

Additionally, the rotor 140 can include two or more permanent magnets.The number and configuration of the pole pieces 123 can also be varied.The operation of the control electronics 130 is selected to account forthe number and position of pole pieces of the stator and permanentmagnets of the rotor. Also, the cap 118 can be engaged with theperipheral wall using other techniques, such as adhesives, welding,snap-fit, shrink-fit, or other technique or structure. Similarly, thefirst face 111 may be formed from a separate piece of material than theperipheral wall 116 and the first face 111, including the inlet cannula112, can be attached to the peripheral wall 116, such as by welding,after the control electronics 130 and the stator 120 have been mountedin the internal compartment 117. The shroud 145 may be omitted andoptionally replaced by other flow control devices to achieve a desiredpump efficiency. As another option, the control electronics 130 can belocated external to the pump 100, such as in a separate housingimplanted in the patient's abdomen, or external to the patient's body.

In some implementations, the dimensions of the housing 110 can be largeror smaller than those described above. Similarly, the ratio of the widthW of the housing 110 to the thickness T of the housing can be differentthan the ratio described above. For example, the width W can be fromabout 1.1 to about 5 times greater than the thickness T. Additionally,the permanent magnet 141 of the rotor 140 can include two or more pairsof north and south magnetic poles. While the peripheral wall 116 and thedividing wall 115 are illustrated as cylinders having circularcross-sectional shapes, one or both can alternatively be formed havingother cross-sectional shapes, such as oval, or an irregular shape.Similarly, the peripheral wall 116 can be tapered such that the housingdoes not have a constant width W from the first face 111 to the secondface 113.

As mentioned above, in some implementations, the blood pump 100 can beused to assist a patient's heart during a transition period, such asduring a recovery from illness and/or surgery or other treatment. Inother implementations, the blood pump 100 can be used to partially orcompletely replace the function of the patient's heart on a generallypermanent basis. In a particular aspect described herein, the moldedinterconnect device 128 carrying the Hall sensor 129 may allow tomonitor the position of the rotor of the pump 100 and may thereby helpto ensure a proper operating status of the implantable blood pump 100.

The preceding figures and accompanying description illustrate exampleprocesses and example devices. But example Hall sensor 129 or moldedinterconnect device 128 (or other components) contemplates using,implementing, or executing any suitable technique for performing theseand other tasks. It will be understood that these processes and partsare for illustration purposes only and that the described or similartechniques may be performed at any appropriate time, includingconcurrently, individually, in parallel, and/or in combination. Inaddition, many of the steps or parts in these processes may take placesimultaneously, concurrently, in parallel, and/or in different ordersthan as shown. Moreover, molded interconnect device 128 may usecomponents with additional parts, fewer parts, and/or different parts,so long as the devices remain appropriate. Moreover, although featuresmay be described above as acting in certain combinations and eveninitially claimed as such, one or more features from a claimedcombination can in some cases be excised from the combination, and theclaimed combination may be directed to a sub-combination or variation ofa sub-combination.

In other words, although this disclosure has been described in terms ofcertain aspects, implementations, examples or generally associatedmethods, alterations and permutations of these aspects, implementationsor methods will be apparent to those skilled in the art. Accordingly,the above description of example aspects, implementations or embodimentsdo not define or constrain this disclosure. Other changes,substitutions, and alterations are also possible without departing fromthe spirit and scope of this disclosure.

What is claimed is:
 1. An apparatus comprising: a circuit board having an outer region, extensions, and end regions, the extensions each having a first end coupled to the outer region, the extensions each extending inward from the outer region to a second end that is coupled to one of the end regions, wherein the extensions are more flexible than the end regions; electrical interconnects disposed at the end regions; and a plurality of sensors, each of the plurality of sensors being mounted to a respective electrical interconnect disposed at one of the end regions.
 2. The apparatus of claim 1, wherein the extensions are configured to flex to direct stress away from the end regions.
 3. The apparatus of claim 1, wherein the outer region is more flexible than the end regions.
 4. The apparatus of claim 1, wherein the outer region is generally circular, and the extensions extend radially inward from the outer region.
 5. The apparatus of claim 1, wherein the outer region defines a closed boundary around an opening defined through the circuit board, and the extensions and end regions extend into the opening.
 6. The apparatus of claim 1, wherein the circuit board has a generally planar surface, the electrical interconnects are disposed at the generally planar surface, and the sensors extend from the generally planar surface.
 7. The apparatus of claim 1, wherein each of the extensions extends along a corresponding axis and each of the extensions has a width perpendicular to the corresponding axis; and wherein the end region located at the end of each extension has a width perpendicular to the corresponding axis of the extension, the width of the end region being greater than the width of the extension.
 8. The apparatus of claim 1, further comprising: a plurality of guide members, each guide member being mounted to one of the sensors in the plurality of sensors; and a carrier configured to attach to the circuit board and engage the guide members.
 9. The apparatus of claim 8, wherein each of the guide members is located at an upper surface of one of the sensors in the plurality of sensors.
 10. The apparatus of claim 8, wherein each of the guide members is an electrically neutral circuit board segment.
 11. The apparatus of claim 8, wherein the carrier has an inner region that connects each of the end regions when the circuit board is received in the carrier, and the carrier has projections that extend outward from the inner region to the outer region of the circuit board when the circuit board is received in the carrier.
 12. The apparatus of claim 1, wherein the plurality of sensors comprise Hall effect sensors configured to detect magnetic fields indicative of parameters of a motor of an implantable blood pump.
 13. The apparatus of claim 1, wherein the sensors are configured to produce data indicative of a position of a rotor of an implantable blood pump.
 14. The apparatus of claim 1, wherein the sensors are configured to output a voltage that is directly proportional to a strength of a magnetic field that is located in proximity to pole pieces of a motor stator and a rotor of an implantable blood pump.
 15. The apparatus of claim 1, wherein the sensors are oriented axi-symmetrically.
 16. A method comprising: mounting sensors to a circuit board to form a sensor assembly; installing a mechanical carrier in a motor assembly, the mechanical carrier defining a predetermined alignment of the sensors with respect to the motor assembly; after installing the mechanical carrier in the motor assembly, placing the circuit board of the sensor assembly in the mechanical carrier; and positioning the sensors in the mechanical carrier such that the sensors are arranged in the predetermined alignment.
 17. The method of claim 16, wherein mounting the sensors to the circuit board comprises mounting the sensors to a circuit board that has extensions that extend to end regions having electrical interconnects disposed at the end regions, the extensions being more flexible than the end regions electrically connecting the sensors to the electrical interconnects.
 18. The method of claim 17, wherein positioning the sensors in the mechanical carrier in the predetermined alignment comprises flexing the extensions of the circuit board such that the sensors are positioned in the predetermined alignment within a predetermined tolerance.
 19. The method of claim 18, wherein flexing the extensions comprises flexing the extensions to a greater degree than the end regions having the electrical interconnects.
 20. The method of claim 16, wherein positioning the sensors in the carrier in the predetermined alignment comprises positioning the sensors axi-symmetrically.
 21. The method of claim 16, wherein positioning the sensors in the carrier in the predetermined alignment comprises positioning the sensors in the carrier such that the sensors are located to detect one or more motor parameters of an implantable 0087002 Spec blood pump.
 22. The method of claim 16, wherein positioning the sensors in the mechanical carrier in the predetermined alignment comprises placing the sensors in the mechanical carrier such that a guide member affixed to each sensor is received in a corresponding slot defined by the mechanical carrier.
 23. The method of claim 16, further comprising affixing a guide member to each sensor of the plurality of sensors.
 24. The method of claim 16, further comprising, after positioning the sensors in the carrier in the predetermined alignment, removing a portion of the circuit board that extends inward beyond the sensors.
 25. The method of claim 24, wherein removing a portion of the circuit board comprises breaking off a portion of an end region along a perforated or scored line across the end region. 